2002年是飞机事故多发之年：
①北航客机在韩国釜山撞山燃烧爆炸；
②乌克兰飞机在空中表演时失去控制坠地燃烧爆炸；
③俄罗斯军用飞机在车臣被恐怖分子导弹击中爆炸；
④华航客机在万米高空因金属熔化而解体．
分析上述事故，只因发生物理变化而失事的是（ ）
A．①②
B．②③
C．①②③
D．④
①北航客机在韩国釜山撞山燃烧爆炸，发生了可燃物的燃烧，有新物质生成，属于化学变化．
②乌克兰飞机在空中表演时失去控制坠地燃烧爆炸，发生了可燃物的燃烧，有新物质生成，属于化学变化．
③俄罗斯军用飞机在车臣被恐怖分子导弹击中爆炸，发生了可燃物的燃烧，有新物质生成，属于化学变化．
④华航客机在万米高空因金属熔化而解体的过程中只是合金的状态发生改变，没有新物质生成，属于物理变化．
故只有④属于物理变化．
故选D．
Last weekend, I was walking across the village green(草坪) when I saw an elderly gentleman on the bench, just overlooking the duck pond. I thought he looked a bit forlorn(被遗弃的) so I went over and sat next to him. After a few 36 about how nice the weather was and how ther  e were a lot of ducks in the pond today, he told me how he used to come with his wife and watch the children feed the ducks with their mums. They didn't have any 37 of their own..So they cherished being together even more.He explained he had been married for 54 years 38 his wife died and how much he missed 39 all the little things with her, like a beautiful sunset. He now lives in a care home. I remarked at how wonderful it must've been to have been married for so long and to have so many happy memories. He took out a large 40 and wiped his eyes and said he had one regret that in all that time he 41 told her how much he really loved her. He showed me a photograph of them when they were young. The photo was taken more than 50 years ago. He couldn't believe how the time had 42 . I tried to comfort him by explaining that his wife would be still 43 over him and he could talk to her 44 he wants and that she knows how much he loved her because she can see into his heart. The old man tried to 45 for blurting out his life story but I hushed him and said how privileged I felt he could talk to me and how much it meant to me. The 46 I learned from this chance encounter is that we must tell the ones close to us how much we love and care for them and not take them for granted. Don't 47 your kind acts until tomorrow; do them today because time flies.
|